A novel fluorescein-based fluorescent probe for detection Hg2+ and bioimaging applications

Mercury has complex biological toxicity and can cause a variety of physiological diseases and even death, so it is of great importance to develop novel strategies for detecting trace mercury in environmental and biological sample. In this work, a new type of green fluorescence sensor FLN based on fluorescein-carbazole was developed. FLN demonstrated a distinct fluorescence enhancing at 525 nm towards Hg 2+ ions due to the “PET-off” (Photoinduced Electron Transfer-off). The binding modes between FLN with Hg 2+ was found to be 1:1 by job plot analysis. The limits of detection of TR for sensing Hg 2+ is down to 40 nM. Especially with low toxicity, FLN was successfully applied for detecting Hg 2+ in living cells.